This invention relates to idling systems for operating a device at a reduced speed when no load is applied to the device. More particularly, this invention relates to an idling system for use with a device that also has a speed control system.
Speed control systems that cause devices such as power producing, transferring and absorbing machines to operate at a fixed speed when a load is electrically connected to the machine are well known in the art. Such speed control systems are commonly referred to as "speed governors". Such speed governors typically are either of the mechanical type or of the electronic type.
Various types of mechanical governors are well known in the art. When a load is typically applied to a power producing device such as an internal combustion engine having a simple mechanical governor, the speed or RPM of the engine decreases significantly below the no load speed. To reduce speed droop upon loading, the sensitivity of mechanical governors may be increased. However, as the mechanical sensitivity of the governor is increased, the engine and control mechanism tend to become unstable.
Electronic speed governors are also well known in the art. Such electronic devices permit more accurate control of engine speed and minimize engine speed droop with load while at the same time decreasing engine instability.
Electronic speed controllers or governors are known which operate the device at a fixed speed or RPM when a load is applied, but cause the device to be operated at a different or lower speed as soon as the load is electrically disconnected from the device. The problem with such idlers is that continuous cycling may occur between the higher governed speed and the idle speed if the load is intermittently applied to the device for brief periods of time. For example, in the construction industry a generator device may be used to power a drill or other construction equipment. The drill or other equipment may be used intermittently by the worker; it may be operated for a few seconds or a few minutes, then stopped for a few seconds, and then operated again. Since the generator that powers the drill or load is constantly operating, it will cycle between the governed speed and the lower idle speed if the idler takes over as soon as the load is disconnected from the generator.